Arm for aerial pickup systems



Dec, 23, 1947.

M. w. MANCINI ARM FOR AERIAL PICK-UP .SYSTEMS Filed Deo. ll, 1943 4 Sheets-Sheet 1 Imn Dec. 23, 1947. M, WUMANClNl 2,433,136

ARM FOR AERIAL PICK-UP SYSTEMS Filed Deo. ll, 1945 4 Sheets-Sheet 2 9 Magi lifzzlzmnl Mancini wnses; l l, 5ML sf gg ,691@ cv. y

Dec. 23, 1947. M. w. MANCINI ARM FOR AERIAL PICK-UP SYSTEMS Filed neef 11, 1945 4 sneeis-sheet 3 m aww I wizzesses;

Dec. 23, 1947. M w. MANClNl 2,433,136

ARM FOR AERIAL PICK-UP SYSTEMS Filed Deo. 11, 1943 4 Sheets-Sheet 4 wi-rzesses: 533%. K

Middel Mlliam Mancini y Patented Dec. 23, 1947 ARM FOR AERIAL PICKUP SYSTEMS Michael William Mancini, Pittsburgh, Pa., assignor to All American Aviation, Inc., Wilmington, Del., a corporation of Delaware Application December 11, 1943, Serial No. 513,834

Claims.

My invention relates to aircraft pick-up and delivery apparatus and more particularly to a pick-up arm therefor.

Customarily, a pick-up arm attached to an aircraft is used to pick up cargo and gliders. To accomplish a pick-up, a ground station is ordinarily used consisting of two upright poles with a pick-up loop stretched between them and held by releasable clips. This loop is connected to a tow line attached to a cargo container or glider. A pick-up arm depending from the aircraft has at its outer tip a releasable hook.

In previous practice the arm has been manually actuated by an operator in the pick-up aircraft. This caused no end of diculty when making pick-ups under adverse conditions at times when extreme ease and speed of control are essential. Furthermore, a rigidly positioned and locked arm was unsatisfactory due to breakage which occurred should the arm strike an obstacle or a pick-up be attempted at increased air speeds. Several types of resilient and releasable positioning devices were tried, including rubber shook cord, but these proved impractical since the amount of resilience was fixed and hence not fiexible enough to suit different conditions of speed, wind, and weight.

Obviously, too much rigidity in the arm may cause breakage, but ample stability must be provided to assure positive engagement vof the hook. The importance of this problem Will be evident when it is appreciated that the loop must remain in contact with the arm from the time the arm first strikes the loop until the loop becomes firmly,

engaged in the hook. Should the arm bounce back at the instant of initial contact with the loop, no pick-up will result since the hook will be carried back by the arm and its engagement in the hook prevented.

While I appreciate that it would be possible to substitute within the scope of my invention various activating and positioning means for the arm, I prefer to employ a hydraulic or a pneumatic device.

In accordance with the invention, the arm is actuated by a piston or diaphragm and a piston rod connected to the arm. Movement and positioning of the arm are resiliently accomplished by fluid under high or low pressure within a cylinder, supplied from a hydraulic or other sys` tem conveniently installed in the aircraft. Furthermore, the operator may control the arm by manipulating a valve located in anypart of theaircraft.

A main object of the invention, therefore, is to provide a pick-up arm which may be quickly and accurately positioned with the aid of a fluid pressure device.

Another object of the invention is to provide control means for actuating a pick-up arm which may be located in any position in the aircraft irrespective of the location of the arm.

Another object of the invention is to provide a resiliently positioned pick-up arm.

A further object of the invention is to provide a pick-up arm held securely but resiliently in pickup position and a safety device whereby excessive impact on the arm will not cause it to break. n

A still further object is to provide control and indicating means whereby the arm may be actuated over a wide range of positions.

A further object is to provide a selector valve, and a pressure responsive device actuated thereby connected to a pick-up arm.

Another object is to provide a relief valve in a hydraulic system so that excessive pressure resulting when the arm strikes an obstacle may be safely vented. l

A further object is to provide a compressible fluid for actuating the arm operating apparatus so that the shock resulting when the arm strikes an obstacle may be absorbed without damage.

Another object is the provision, in a compressible fluid arm actuating apparatus of a stop mechanism for positively positioning the arm.

Figure 1 is a fragmentary elevation of the structure of a hydraulic arm actuating apparatus.

Figure 2 is a fragmentary perspective view of a part of the structure shown in Figure 1.

Figure 3 is a section taken along line 3 3 of Figure 1.

Figure 4 is a diagrammatic perspective of a type of hydraulic cylinder partially exposed.

Figure 5 is a diagram of a hydraulic arm actuating system showing the arm in the pick-up position.

Figure 6 is a diagram corresponding to Figure 5 showing the arm in the raised position.

Figure 7 illustrates how the invention may be employed to install the arm, pivot and bracket in an otherwise inaccessible location.

Figure 8 is a fragmentary elevation of an aircraft showing another installation of the arm and cooperating mechanism.

Figure 9 is a partly fragmentary somewhat diagrammatic perspective View of a pneumatic arm operating mechanism.

Figur-e 10 is an elevation of thearm actuating apparatus of Figure 9 with the piston extended and the arm in the raised position. Y

Figure 11 is a bottom View of a portion of the structure of Figure but with the piston retracted to its maximum position.

Figure l2 is a detail perspective of a piston travel regulating device.

Figure 13 is a detail perspective of the structure of Figure 12 shown in an alternative regulating position.

Figure '14 is a diagram of the pneumatic arm' actuating system showing the arm in the pick-up position.

Figure 15 is a diagram corresponding 'to-- li'ltley 14 but with the arm shown in the raised position.

In one form of the invention, shown by/'Figures 1 to 5, an arm 29, preferabl'yof wood, is clamped in a trunnion member 2I by bolts 22. Trunnion 2| consists of arm supporting: tubular sectoni welded at right angles to tubular member. .24 which, after assembly in bracket 25, is secured by bolt 26 to bearing sleeve 21, as shown in Figure 3. Annular bushings 28 pressed into side members 29 of bracket 25 providebear'ing surfaces and support for bearing sleeve member 21 Vand trunnion 2 I.

y Formed integrally with the trunnion are ver#Y tica-l "ns 3'9 with' which an actuating cylinder 3ft cooperates tol pivot truilnion 2'IV and Vsleeve 2'!Y in bushings 28.` Cylinder "35| is connected to 'fins 3l)A by pin 32vv'fh'i'c'l'iv passes through an eye 3'3" `of` enlargederid of rod 34, which in turn forms an extension 4or piston rod' 535;

Means for adjusting the Veffective working length of piston rod 35 is 'provided by vthreaded engagement `bem/'een `rod 84 vandv piston rod 35, locked by nut 36. Excess piston travel is prevented by stop nut 3.1' externally threaded on piston rod 35 4and locked by' nut 3'8. Additional adjustment Aof the relative position of the piston and arm may be provided 'by a plurality of holes 39 Ain Tvfins l39. The forwardiend of `cylinder 3l is pivotally supported by `bracket '49 lfastened vbyl bolts v'1H to mounting 42 which attached to principal mounting bracket25 by means of bolts' 43'. /Bracket'25ijs attached by means of bolts 44 through blocks 45'to' a'structural member of an aircraft :f6

Hydraulic cylinder '3 I ,shown diagrammatically in 'Figure' 4, has 'piston rod 35 integralwith .a piston 4'I'adapt'ed'to reciprocate therein. 'Fluid'is admitted into or out of vthe forward end'4'8 ofthe cylinder vthrougli ori'ce A"49 and the rear end 59 through-drinne 5I. vManfolds'sz permit veasyattachment of 'hydraulic tubing andiittings to the cylinder and Yorices. .'Packing'nut '53 prevents fluid iromesc'a'ping from around'the'rod. Itwill be obvious from the above that movement ofzth'e arm is controlled by motion vof the -piston and piston rodr within 'the cylinder. Y

Themanner :in which this Vis accomplished may b'e understood by -referringnow'to Figures 5 and 6.

Figure 5 shows liuid being admitted to the cylinder through 4"the port :49 which forces the piston 41 tothe right'in the'gurethereby'lowering thearm. Port 4`91is 'connected'to line V54 and port155of a-selector valve 56. Whenit is desired to introduce fluidunder' pressure into'the forward endfof'the cylinder through 'port-9, barrelS'I 'of the selector valve isturned-so thatjpassage 58 connects port 59 with port 155. 'Port 591s connected to the outlet or pressure side of anordinaryfhy'draulicipump 69 by means ofline 6 I. The

inlet side of pump 69 is vrconnected xto ajreservoir Y 4 reservoir 62 through line 64, port 65 of the selector valve, passage 66, port 61, and line 68. It will be obvious that proper positioning of barrel 51 simultaneously allows uid to enter port 65 and exhaust through port 61. When the arm is lowered to the desired angle, as indicated by pointer 68 on quadrant 69, barrel 51 may be turned, if desired, to an intermediate position preventing. turtlier pressure from being introducedv into line 54'.

VSince the fluid employed in the system of Figure 5 is substantially incompressible, for example i asfoi1l,asuitable relief valve 19 is connected between pressureline 54 and return line 68. It will beunderstood that` the setting of relief valve 'I9 :is 'su'c'h that'l the ar-m 20 will be maintained in pick-up position with only sufficient force to insurerpositivefengagement of the hook 1 I. Should this forcebe exceeded as, for example, a landing be attempted with the arm down, the excessive pressure thereby created in the forward end 48 ofcylind'er 3| willcause the relief valve -'I'9f to open and to permit fluid toreturn to thereservoir.

In Figure 6 the ilow of `pressure Huid to they opposit'ei'end :59 fo'f lthel cylinder is illustrated. This occurs when barrel" 51 'of selectorvalve 5t' is turned to `connect port 55 with port 6.1 and portI :59 vwith port 65, pressure now be'ing 'applied to the other sidefof piston 41, and forward end 628' of cylinder 31 Ibeing 'connected to the return line 58, the piston travels vto the leftV in Figure 6 thereby raising `the arm to asubstantially Yhorizontal position which lmay likewise be detere mined by fthe' operator'from the pointer B8'.

As'the arm travels downwards,-actuated yby the response of the piston-and piston rod to the-pressure ofthe hydraulic fluid, it may be stopped in any' position by'reg-ulating the yselectorv valve until it is in `neutral shutting olif the valve entirely. The operator vhas complete'positve'control of the arm at -every point, assuring `a wide 4range of operating positions. It willbe yapparent that a suitable means for ascertaining the position of the'arm may 'be provided. Such a device, shown diagrammati'cally Aatiigures andlffmay consist of a pointer l(iwhic'h'may be affixed to the arm actuating `trunnion '2fI or ns 30 -orv some other moving part. The pointeris kdesigned. to travel across a, suitably calibrated semicircularplate-or quadrant 69 adapted to indicate the position of thearm with respect to-the aircraft.

As soon as `the-arm has reached the desired horizontal position, the selector valve may be turnedto intermediate or Lneutral position thus retaining the 'arm29 inrplace. VUnder these con-v ditions, it will tbe apparent Ythat `the `pump 69 should be stopped toavoidfexcess'ive `pressure in lines l6I and*64 or'if^desi1'ed,aJ second relief valve I2may be placed between line 6I "and reservoir '62.

Another manner in which -a pick-'up 'arm may be resiliently Vpositioned 'is illustrated inFigures 9` to '15in which a vacuumbrpressure responsive device'may be employed 'toadvantage. rI 'he arrangement foru'id vcontrol depicted lin Figs. 5 and 6 may also be employed in conjunction with the vacuum `or pressure responsive mechanism now to be described.

Arm 'I3 is clamped in `sleeves "I4 centrallypositioned on'ayoke 'i5 of triangular conguration consisting of diagonal members 'I6 an'd'axle'lnem-l ber 11 pivotallysupported vbyintegral'brackets 'i8 in'g frommenb'erl conveniently constructed of tubing whichmay be -:it-structural part'of'theair-` threaded to the end of piston rod 85 and providing adjustment of the operating length of the piston rod. A pair of lugs 8S integral with the piston rod cooperate with a piston travel regulating device 81 consisting of an outer slotted sleeve 88 welded to the top plate 89 of a bracket 99 centrally drilled to accommodate the piston rod B5. An inner slotted sleeve 9| rotated by pin 92 is actuated by a flexible cable control 93 having a handle 94 set in the flooring or other convenient location in the aircraft. Bracket 95 and clamp 9S serve as an anchor for the cable control. A pneumatic cylinder 91 of any suitable type, such as that in use on automatic booster brakes, and having a housing made in two hollow parts 99 and 99 is bolted by bolts |00 through spacer blocks IOI to bracket 90. Within the cylinder 91 and firmly secured around its outer periphery is a flexible diaphragm |02 which is bolted between the hollow chambers 98 and 99. For purposes of convenience, hollow chamber 98 will be designated the forward chamber and hollow chamber 99, the rear chamber. The diaphragm |02 is attached to one end of the piston rod 85 by plates |03 riveted to each other through the center of the diaphragm |02 and to one of which plates the end of the piston rod may be welded. Gland It provides effective sealing means for'the aperture through which the piston rod moves.

Tabs |05 of the bracket 90 are each pivotally mounted with bolts |05 to clevises |01 integral with a supporting member |08 attached to the previously mentioned chief supporting member 8|. Additional supporting members |09 may be provided as required.

Figures 12 and 13 illustrate diagrammatically the operation of a travel regulating device similar to that shown in Figures 9, 10, and 11. A fixed outer sleeve 88 has two longitudinal slots |I0 adapted to receive lugs 86 on the piston rod 05. The inner sleeve 9| is rotatable and similarly slotted to receive the lugs. Traveling in a transverse slot III in the outer sleeve 88 is a pin 92 which is resiliently attached to the inner sleeve 9|' in such a manner that movement of the pin 92' in transverse slot III rotates inner sleeve 9| to cause the slots in the inner sleeve to become aligned with thev corresponding slots IIB in the y outer sleeve. This rotation is effected by any suitable means which may be attached to pin 92. It will be understood that when the inner sleeve is in the position of Figure 13, forward travel of the piston rod is limited since the lugs 8S are abutted on the inner sleeve 9|. However, when inner sleeve 9| is turned to the position of Figure 12, the piston is permitted to travel farther forward which in turn serves to lower the arm to a nearly Vertical position.

Operation of the arm is effected by movement of the diaphragm in the cylinder acting through piston rod 85 and lever 82 in a manner very similar to the hydraulically actuated piston of Figures 1 to 6. The pneumatic control mechanism is also generally similar to a hydraulic control system.

Such a control system is shown diagrammatically in Figures 14 and 15. The intake port II2 of a pump I I3 is connected to an accumulator I4 through a check valve I I5 and line It. A fourway selector valve III, illustrated diagrammatically, has four ports, one of which IIS is connected to the accumulator; another port |I9 is open and serves as a vent; the third port |20 is connected to the forward chamber 98 through line IZI and chamber port |22; the fourth port |23 of 6 the selector valve is connected to the rear chamber 99 by line |24 and chamber port |25. When the selector valve is turned to the position shown in Figure 14 so that the forward chamber 98 is connected to the accumulator through ports |I8 and |20 and rear chamber 99 is vented through ports ||9 and |23, the diaphragm will be urged forwardly by external pressure entering through port ||9 and the arm will be lowered to its normal operating position somewhat as indicated in Figure 14. The position indicated by dotted lines in Figure 14 shows the approximate position of the arm when the piston is permitted its maximum forward travel by suitably turning the inner sleeve as described above.

Figure 15 illustrates the position to which the selector valve is turned to raise the arm. By turning a plug |26 of the valve so that the rear chamber 99 is connected to the accumulator through port I I8 and port |23 and forward chamber is vented through port H9 and lport |20, the low pressure previously existing in the forward chamber 98 may now be replaced by atmospheric or other pressure which urges the diaphragm and piston towards the rear chamber 99 which operation is substantially the reverse of that previously described for lowering the arm.

The vacuum or low pressure created by the pump and stored in the accumulator is maintained by means of check valve ||5 which is located between the pump and the accumulator.

The accumulator provides, in addition to its function of actuating the diaphragm, a convenient resilient cushion for absorbing any sudden stress which may be imposed upon the arm to suddenly change its position.

The arm may, of course, be stopped in any position by putting the valve into neutral, but I prefer a positive means of arm positioning, the piston travel regulating devices, whereby as the piston rod is drawn into its retracted position by the contained vacuum pressure acting on the ilexible diaphragm, the lugs of the regulating device thrust against the unslotted edge of the inner sleeve preventing the piston from. utilizing its maximum stroke to carry the arm beyond its predetermined pick-up position. If in order to assure the arm clearing a trailing load, a substantially vertical arm position is desired, the slots may be placed in alignment so that the lugs of the piston rod may t into the slots allowing the piston rod to be fully retracted and permitting the arm to travel down into a substantially vertical position.

Figures '7 and 8 illustrate how my invention lends itself to installation in various types of aircraft.

Bracket 25, which maybe a mounting for either` a hydraulic or pneumatic type of cylinder, is mounted in Figure 8 near a hatch |21 or bomb bay in a pick-up aircraft. Line |23 attaches hook 'II to shock absorbing winch |29, which is positioned at any convenient location inside'the fuselage. The line may be guided around pulley |30 to carry the load after the hookl has been disconnected from the end of the arm and the glider or other load is being towed.

In order to prevent the arm in its raised position from interfering with control surfaces on the aircraft and to permit easy access to the tip of the arm or installing the hook thereon, the pivot and mounting bracket may be located considerably forward of the hatch, as shown in Figure '7. In ordinary flight, the bomb bay door I3| is closed and the arm raised on they Outside 

